Accelerator of rubber vulcanization



Patented Oct. 4, 1932 UNITED Si rras PATENT OFFICE JAN TEPPEMA, OFAKRON, OHIO, ASSIGNOR TO THE GOODYEAR TIRE & RUBBER COMPANY, OF AKRON,OHIO, A CORPORATION OF OHIO ACCELERATOR on RUBBER voLcAmzArIon NoDrawing. Original application filed January 10,1928, Serial N 0.245,808. Divided. and. this application filed January 10, 1930. SerialNo. 420,012.

My invention relates to the treatment of rubber and rubber-likesubstances and it has particular relation to methods of vulcanizingthese materials.

This application is a division of application Serial Number 245,808,filed J anuary More specifically, the invention has for one of itsobjects the provision of a class of materia-ls which, when incorporatedin rubber compounds, bring about rapid vulcanization and a producthaving excellent aging qualities.

' Another object of the invention consists in the provision of a classof materials having the above enumerated characteristics, which may bereadily manufactured and easily dispersed in rubber compounds.

It has been observed heretofore that certain 29 mercaptothiazoles andtheir derivatives, when incorporated in vulcanizable rubber compounds,cause rapid cures and a high quality of product. This invention consistsin the discovery that certain compounds of this class 25, may be reactedwith nitroso compounds, such as nitroso dimethyl aniline and nitrosonaphthol, to produce compounds which are also sufficient acceleratorswhen incorporated in rubber.

To manufacture compounds of this class, a thiazole, such asmercaptobenzothiazole, is mixed with a nitroso compound, such as nitrosodimethyl aniline or nitroso naphthol, the materials then being heated tothe melting point. At this temperature a vigorous reaction occurs whichis permitted to continue without the application of further heat untilit is completed. The resultant mass, after cooling, is obtained as ahard brittle product to which may be ground to a powder. The

powder may be used without further treatment or it may be treated withammonium hydroxide in order to remove any unreactedmercaptobenzothiazole which may be contained therein.

The reactions taking place when mercaptobenzothiazole is heated withmtroso dimethyl aniline or nitroso naphthol may be represented by thefollowing structuralformulee S on 2 CSH+VOYN.-

The materials prepared in accordance with the preceding method may beincorporated in most of the standard rubber stocks withsatisfactoryresults. The following is an example of a formula which hasbeen found by experiment to yield excellent results when either thenitroso dimethyl aniline saltor the nitroso naphthol salt ofmercaptobenzothiazole is employed as an accelerator:

Samples of material prepared in accordance with the preceding formulawere subjected to vulcanization at various temperatures and for varyingperiods of time. These samples were then subjected to physical tests inorder to ascertain their tensile strength and elasticity, both beforeand after an aging test which was conducted in an oxygen bomb under apressure of 150 pounds per square inch and at a temperature of 50 C. fora period of six days. The results of these tests are contained in theappended tables.

Reaction product Q-mercapiobcnzothiazole p/H/HTOSO dimeth'yl aniline,ammonia emtracted Original Steam Tensile. Per t E in f Per cent Curepresstrength, elon 500%; 700% weight;

sure kgslcni. elong. elong. increase- Time Pounds :30 at 180 S00 27 94:15 85 950 10 26 :30 164 880 18 60 201 850 24 87 1:00 192 810 28 1042:00 228 790 33 123 Aged in omggen bomb 6 days at 0.

Reaction product l-nitroso-naphthol Q-WLG'YCGPtODQW zothiazole, ammoniaextracted Original gen bomb'o days at 50 0.

It will be observed from the tables that compounds containing either ofthe accelerators described are well cured within a comparatively shorttime. I-Iowever,.comparatively long heating at the vulcanizingtemperature does not result in excessive overcure. It will also beobserved that the 'employment of these accelerators gives rise to aproduct having excellent aging qualities.

Although I have described in detail only the preferred embodiments ofthe invention, it will be apparent tothose skilled in the art that theinvention is not limited thereto, but that various modifications maybemade C- S N-R, N 2

in which R represents a naphthalene nucleus.

2. A rubber product vulcanized in the presence of a material having thefollowing structural formula in. which represents a naphthalene nucleus.r

3. A method of treating rubber which comprises'vulcanizing it in thepresence of the reaction product of a nitroso naphthol and amercaptothiazole.

4, A method of treating rubber which coinprises vulcanizing it in thepresence of the reaction product'of a mercaptothiazole and Signed atAkron, in the county of Summit and State of Ohio,'U. S. A., this 8th dayof January, '1930.

JAN TEPPEMA.

therein without departing from the spirit .of V

invention or from the scope of the appended claims wherein it isintended to claim all patentable novelty inherent in the invention. 7

What I claim is: V

1. A method of treating rubber which comprises vulcanizing it in thepresence of a material having the following structural formula i

